Pivoted bucket loader



. Oct. 21,1958] D. scHwARTz ETAL 2,357,064

PIVOTEDA BUCKET LOADER 3 Sheets-Shet 1 Original Filed Aug.v 9; 1951 INVENTOR v Daniel M. schymrtz Donald, E H endrickson' D. M. :SCHWARTZ ET AL 2,857,064

PIVOTED BUCKET LOADER s Sheets-Sheet 2' Original Filed Aug. 9, 1951 3 w ow E INVENTOR DANIEL M. SCHWARTZ DONALD E. HENDRICKSON ATTORNEY United States 2,857,064 PIVOTED BUCKET LOADER Daniel M. Schwartz and Donald E. Hendrickson, Salt Lake City, Utah, assignors, by mesne assignments, to The Eimco Corporation, Salt Lake City, Utah, a corporation of Delaware Original application August 9, 1951, Serial No. 241,857,

now Patent No. 2,746,625, dated May 22, 1956. Divided and this application April 11, 1956, Serial No. 577,578

4 Claims. (Cl. 214131) This invention relates to a loading or excavating machine adapted to be used in mines and tunnels where, due to limited headroom and confined spaces, compactness, mobility and ease of control are essential features.

It is an object of the invention to provide an improved loading machine having a pivotally mounted arm adapted to carry an overhead shovel bucket.

Another object is to provide an improved device of the type described, having a variable torque drive.

A further object isto provide such a device having a variable torque responsive hydraulic motor or a variable torque transmission connected to the pivotal loader arm or both.

Another object of the invention is to provide an improved loading machine having a pivotally mounted loader arm, and a conveyor adapted to receive the mucked material.

Another object is to provide such a machine having positive bucket return from the discharge position.

Further objects are to provide a pivoted arm material handling machine wherein the arm may be positively held in the down position for fine grading or heavy digging and wherein the material handling implement is prevented from riding over obstructions and the like.

These and other objects and advantages of the invention will appear more fully in connection with the illustrative embodiments of the invention shown in the accompanying drawings, in which:

Fig. 1' is a fragmentary left side elevation of a pivoted bucket loader embodying the principle of the invention in combination with a mobile conveyor;

Fig. 2 is a top plan view of the machine shown in Fig. l; and

Fig. 3 is a diagrammatic representation of a hydraulic system of the pivoted bucket loader of the invention.

With reference to the illustrative embodiments of the invention and in particular to Figs. 1 and 2, there is shown an excavating apparatus embodying the principles of the invention which generally comprises a main frame or body 10, mounted on crawler or self-laying track units 12.

The main frame carries a pivoted loading bucket assembly 14 secured to the forward end of the machine, and adapted to load material into a conveyor 16 pivotally secured to the frame 10.

The prime mover, and the bucket, conveyor and traction motors, generally designated 18 and 20, respectively, are housed beneath the endless belt conveyor and between the self-laying track units of the loader.

The bucket assembly 14 comprises a pair of bucket pivoting arms 22 secured to shaft 23 pivotally mounted in bearings 24 carried by the side frames 26 of the machine. Between the pivot arms 22, and at their lower ends, a muck bucket 28 is rigidly secured, for example, by welding or by bolts 30 as shown in the drawings.

Also secured to shaft 23 between the pivot arms 22 and the side plates 26 is a pair of members 32 having camshaped outer faces 34.

cams at 46 and 48, respectively. The flexible draft members are shown in the drawing as flat cable chains which are highly. effective for riding on cam surfaces. The cam surfaces 34 and 38 are shaped to provide a digging-dis? charge cycle having a high torque, low'speed portion at the beginning of thedigging operation which gradually develops into a high speed, low-torque portion at the end of the discharge cycle. The camfaces of cams'32 and 36 and their relative positions with respect'to each other are selected to provide the largest effective radii from the center of the pivotal mounting of the pivot arms 22-to the point of tangency of chains 44 with cams 32, and the smallest effective radii from the center of the shaft 40 to the point of tangency of chains 44 with cams 36 .when the bucket is inthe digging position; the effective radii of cams 32 decreasing to a minimum and the effective radii of cams 36 increasingto a maximum as thebucket approaches the discharge position, thus providing a very effective variable ratio drive for the excavating machine.

The relative positions of. cams 32 and 36 as shown in Figs. 1 and 2 of the drawings provide. a low speed high torque zone during the digging portion of the diggingdischarge cycle and a high speedlow torque zone during the discharge portion of the cycle. I i The bucket 28 in an advantageous form of the invention is adapted to discharge on to the lower end. of an endless belt conveyor 16.

The conveyor belt has a conventionally driven pulley 52, tension pulley 54 and guide pulley 56.- The. forwardend of the conveyor may be pivotally mounted. on the mainframe 10 of themachine, while the rearward portion of the conveyor is supported by a power jack assembly 58, enabling the operator to raise or lower the discharge end of the conveyor. This provides 'an extremely versatile loader as the discharge height oftherco'nveyojr may be lowered inv shafts and tunnels havinglow clearances or the conveyor may be adjusted to memoir efli cient height for various shuttle cars used to receive the conveyor discharge.

With reference to Fig. 3 of the drawings, diagrammatically representing an advantageous form of hydraulic power system for the pivoted bucket loader, 18 is the prime mover which may be, for example, an electric motor or an internal combustion engine. Variable volume delivery pumps and 62, such as the radial piston or radial vane types, having individual'flow control members 64 and 64 of the fluid pressure type, are driven by prime mover 18. In the preferred form of the invention, variable delivery pumps 60 and 62 are the pressure responsive type wherein at high pressure the volume delivered by the pumps is a minimum, sure the volume rises to a maximum.

The suction side of the pumps are connected by conduits 66 and 68, respectively, to a common supply line 70 leading from a pair of filters 72 and 74 secured to the main reservoir 76 for hydraulic fluid.

The delivery side of pump 60 is connected by conduit 76 to the loader drive control valve 78, at valve port 80. The traction control valve 78 distributes the pressure fluid to reversible traction motor 82 through valve ports 84 and 86, and from port 88 to the reservoir 76 through filter cartridges 90 and return lines 92 and 94.

Conduits 96 and 98 are the pressure supply or return lines for traction motor 82 and are connected to valve ports 84 and 86.

The valve 78 is provided with a valve spool 104 and and at low prescontrol lever 106. The spool has three positions designated A, B and Cforward, reverse and neutral,

respectively, as more fully described in our co-pending application Serial No. 241,057, filed August 9, 1951, now Patent 2,746,625, issued May 2, 1956 of which this application is a division.

The delivery side of pump 62 is connected by means of conduit 110 to the bucket control valve 112 through valve port 114. This valve distributes the pressure fluid to the bucket pivoting arm motor shown in the drawing as fluid pressure reversible motor 116, through valve ports 118 and 120, and from port 122 to the fluid reservoir 76 through filters 90 and return lines 92 and 124.

Conduits 126 and 128 are the pressure supply or return lines for the motor 116, and are connected to valve ports 118 and 120, respectively.

The valve 112 is provided with a spool 130 and control lever 132, the spool having three positions designated D, E and F," the bucket up, down and neutral positions respectively. In the drawings, this valve is shown in the neutral position so that fluid pressure enters the valve through port 114 and is directed to the reservoir return line 124, through port 122. The spool ports to the bucket actuating motor are blocked when the valve is in the neutral position preventing fluid flow in conduits 126 and 128, thus providing a hydraulic brake for the bucket assembly.

It will be seen that with the torque responsive motor above described, coupled with the variable torque transmission, characterized by a power demand cycle including a high torque, low speed portion during the digging operation, and allow torque high speed portion during the dumping operation, a very eliective loader is provided.

The utility of the variable torque transmission is thus increased by providing the loader with the torque responsive motor.

From the foregoing description of the invention, it will be seen that an improved loading machine having a pivoted loader arm adapted to carry an overhead shovel bucket is provided, which is especially adaptable for use in mines and tunnels, due to its compactness and ease of control. Further by the provision of the improved hydraulic system having a single prime mover adapted to supply power to a plurality of fluid pressure operable motors, each having an individual power-torque demand, great savings in space, cost of construction and maintenance are attained.

This application is a division of our co-pending application Serial No. 241,057, filed August 9, 1951, now Patent 2,746,625, issued May 2, 1956.

We claim:

1. A material handling machine comprising a main frame, an arm, means mounting said arm for pivotal movement adjacent the forward end of the main frame, cam means having a cam surface mounted for pivotal movement with the arm, a motor-driven cam means having a cam surface supported on the frame, and flexible draft means connecting the cam surfaces for actuating the arm, said cam surfaces being shaped to provide a varying torque in successive angular positions of the arm.

2. A material handling machine comprising a main frame, an arm, means mounting said arm for pivotal movement adjacent the forward end of the main frame, cam means having a cam surface mounted for pivotal movement with the arm, a motor-driven cam means having a cam surface supported on the frame, and flexible draft means connecting the cam surfaces for actuating the arm, said cam surfaces being shaped to provide a continuous torque-speed ratio from a high torque, low speed zone to a low torque high speed zone.

3. In a material handling machine having a main frame, an arm, a material handling device carried at one end of the arm, means mounting the other end of the arm for pivotal movement adjacent the forward end of the main frame, means for pivoting the material handling device from a low forward position to an elevated position, said means comprising cam means having a cam surface mounted for pivotal movement with the arm, a motor-driven cam means having a cam surface supported on the main frame, and flexible draft means connecting the cam surfaces for actuating the arm, said cam surfaces being shaped to provide a varying torque in successive angular positions of the arm.

4. The invention defined in claim 1 wherein said cam means mounted for movement with the arm and said motor driven cam means have complementary cam surfaces.

References Cited in the file of this patent UNITED STATES PATENTS 

